Ford: 04 Ford Ranger

Question
greetings Sir:
04 Ford Ranger. 89K miles. Intermittent start problems. Truck will run fine, then out of the blue it won't start. Cranks over but no ignition. If I wait a couple hours, will start. Replaced fuel pump relay, worked fine A couple weeks, then same problem. Local mech. Can't find problem because the truck will start when I take it to him. New mech. Wants to replace fuel shut off under front seat. Big money and won't guarantee it. Any suggestions??? Thank you in advance for your time..
Jim

Answer
Hello, you say no ignition, did they confirm no spark or no fuel when it won't start ? The inertia switch was a very common problem but this will cause a no fuel no start condition. If you are having an intermittent no spark condition, I would have them take a peak at the crank shaft sensor . While it is not starting and they have a computer I assume , you would watch for an engine rpm missing while cranking it over . If this is missing then replace the crank sensor. If it is a fuel concern, I would agree with the intertia switch.